Warped Brake Rotor?

I have a shaking or vibration when applying the brakes from a moderate to high speed. The front brakes were done by the dealer 2 - 3 years ago but only 7 or 8 thousand miles, maybe less put on the car since then. The dealer says warped rotors are causing the vibration which means they probably didn't turn them when they did the brakes.

Is it better to replace the rotors or can I have them turned, assuming they have never been turned and if they have that there is enough left to turn? It seems I read somewhere that it is better to just replace them on a cadillac but I can't find that thread so don't know if I read that or not.

Any issue's with O'rielly or Autozone rotors? I did read on this forum that all rotors are made in China. Probably at the same plant...

What about the pads? There should be alot of pad left (haven't looked yet), if so is it alright to reuse them or might warped rotors have damaged them in some way that is not easily visible?

Thank you for any and all advice. This is my folks car and I want to do it right (unlike the Cadillac dealership)

Brian